Commercial cooking ovens (e.g., such as rack ovens) commonly burn gaseous fuel and pass the combustion exhaust gases through heat exchange tubes of a heat exchanger and then up a stack and through an exhaust system to be delivered external to the oven. Cooking air is recirculated from the cooking chamber past the heat exchange tubes to pick-up heat, and the heated cooking air is then delivered back to the cooking chamber. The combustion exhaust gases may have a relatively high temperature (e.g., on the order of 625 to 725 degrees F. when the oven is set for operation at 525 degrees F.), and delivery of the combustion exhaust gases to the exhaust system represents wasted heat and, accordingly, reduced oven efficiency.
It would be desirable to provide an oven that makes use of the combustion exhaust gases after the heat exchange operation, so as to reduce the wasted heat and energy during oven operation.